We have developed a method for cutting intact genes out of Plasmodium DNA with mung bean nuclease. The intact genes are then ligated into an expression vector in order to make a recombinant gene bank containing genes from all stages of the parasites life cycle. We have also analyzed what types of DNA structures are involved with mung bean nuclease cleavage and modified the reaction conditions used so that this procedure works with the DNA of many higher eucaryote. From gene banks produced in this fashion we have isolated 1) a gene whose sequence has been useful in the preparation of a trial vaccine for malaria, the circumsporozoite gene on P. falciparum, 2) genes that are specifically produced in the sexual stages of P. falciparum, and 3) a gene that is involved in pyrimethamine resistance.